A situation often arises in sleeping environments in which two people share a common bed and in which the two people have decidedly different preferences in the extent of bed covering for warmth, etc. This situation is perhaps best described as differences in temperature preference between such sleepers in a common bed. Often, one partner prefers cooler temperature (therefore fewer blankets) while the other prefers warmer temperatures (therefore more blankets). In a standard double bed, queen size or king size arrangement suitable for use by two persons simultaneously, an undersheet is placed upon the upper surface of the mattress and is somehow folded under or secured thereto. Often, the undersheet is a so-called fitted sheet which defines side portions which constrict about the mattress periphery. An upper sheet overlies the undersheet and the user's typically sleep between the undersheet and upper sheet. In most instances, one or more blankets are then laid upon the upper sheet for the desired warmth. In a standard bed arrangement, the sheets serve a very practical function in that the upper and lower sheets are the only portion which touches the sleeper's body. As a result, replenishing the bed for other users is a simple matter of washing the sheets and pillow cases while leaving the blankets as they are. Over time, the sheets are repeatedly washed while the blankets may be washed from time to time. This situation is preferred due to the difficulty associated with washing blankets. The term blanket used in this application will be understood to embrace any of a number of blankets, comforters and quilts utilized for providing thermal insulation for sleeping persons. As a result, the term blanket embraces conventional blankets, knitted blankets, various types of comforters and quilts or the like. Such blankets and similar materials are often "dryclean-only" type materials. Those which are washable are exceedingly difficult to handle and require extended drying and so on.
The differences in temperature preference between sleepers means that one sleeper desires fewer blankets and coverings while the other desires more. Many times sleepers attempt to distribute blankets upon the bed as half coverings to accommodate this diversity. In addition, electric blankets which utilize relatively thin blankets having electrically powered heating coils therein are often provided with dual controls allowing each user to separately adjust the degree of heating in one side of the bed. While such dual control zone type electric blankets are able to provide accommodation of temperature preferences between sleepers, a great number of people prefer not to use an electric blanket for various reasons. As a result, the need in the art for effective bedsheet and blanket combinations for accommodating diverse sleeper preferences is substantial. In response to this substantial need, practitioners in the art have attempted to provide satisfactory practical and effective bedsheet and blanket combinations.
For example, U.S. Pat. No. 5,287,573 issued to Ritacco sets forth a pair of color-coordinated fitted bedsheets positioned overlying a bed in which each sheet is composed of a flannel material and a cotton-polyester blend material joined into two halves running along their respective lengths. The flannel half sheets are preferable for those desiring warmth during cooler months of the years while the cotton polyester blend half sheets are preferable for use by their bed partner desirable a cooler feeling.
U.S. Pat. No. 5,199,121 issued to Payne sets forth an ADJUSTABLE FILL COMFORTER having an outer fabric shell and a fill of down or down-like material. A top panel and a bottom panel are formed about the periphery of the envelope and facilitate the shifting of fill material between one portion of the comforter and another.
U.S. Pat. No. 4,802,251 issued to O'Dell sets forth a TOP AND BOTTOM BED-SHEETING COMBINATION being coupled along one or more edges tending to maintain reasonable order and neatness of the bed linens at the side and/or foot portion of the bed. An embodiment is shown for a double bed which provides a central entry of a person between the coupled sheets.
Additional early attempts at solving the temperature difference preferences between common bed sleepers are set forth in U.S. Pat. No. 3,072,776 issued to Quennville and entitled BED COVERING; U.S. Pat. No. 3,331,088 issued to Marquette and entitled BLANKET WITH CHANGEABLE THICKNESS VARYING PANELS; U.S. Pat. No. 3,508,285 issued to Marquette and entitled BLANKETS WITH MULTIPLE PANELS OF VARYING WARMTH CHARACTERISTICS and U.S. Pat. No. 3,530,516 issued to Marquette and entitled BLANKET WITH INTERCHANGEABLE HALVES.
While the various prior art devices directed to the problem of thermal preferences between sleepers have improved the art generally and in some instances enjoyed commercial success, there remains nonetheless a continuing need in the art for apparatus which more effectively and more efficiently solves the thermal difference preference problem in an easier to use system.